GCSE Physics - Internal Energy and Specific Heat Capacity #28
Summary
TLDRThis video explores the relationship between an object's internal energy and temperature through the concept of specific heat capacity. It explains that internal energy consists of potential and kinetic energy, with the latter being crucial for temperature changes. The script introduces specific heat capacity as the energy required to raise a substance's temperature by one degree Celsius and demonstrates its application with a practical example. The video concludes with a calculation to find the final temperature of water after energy transfer, highlighting the importance of insulation in real-life experiments.
Takeaways
- 🔥 Internal energy is the total energy stored by the particles in a substance or system, often divided into potential and kinetic energy.
- 🌡 Kinetic energy, which is related to the movement of particles, is the key component affecting temperature when a substance is heated.
- 🌡 Temperature is a measure of the average internal energy of a substance, with higher internal energy correlating to higher temperature.
- 🔄 Materials vary in the amount of energy required to change their temperature, which is described by specific heat capacity.
- 💧 Water has a high specific heat capacity, requiring 4,200 joules to raise the temperature of 1 kg by 1 degree Celsius.
- 🌀 Mercury has a much lower specific heat capacity, needing only 139 joules to heat 1 kg by 1 degree Celsius.
- ⚖ The specific heat capacity can be defined as the energy needed to raise the temperature of 1 kg of a substance by 1 degree or the energy released when it cools.
- 📚 The change in internal energy can be calculated using the formula: ΔE = m * c * ΔT, where ΔE is the change in internal energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.
- 📈 An example in the script calculates the final temperature of 800 grams of water after 20 kilojoules of energy transfer, using the specific heat capacity of water.
- 🔢 The calculation involves converting units to kilograms and joules, and then applying the formula to find a temperature change of 5.95 degrees Celsius.
- ⚠ Real-world energy transfer may not result in the exact temperature increase due to energy loss to the surroundings, especially in an open system without insulation.
Q & A
What is internal energy?
-Internal energy is the total energy stored by the particles making up a substance or system.
How is internal energy divided?
-Internal energy is often considered to be made up of two parts: potential energy stores and kinetic energy stores.
Which part of internal energy is related to temperature?
-The kinetic energy store is related to temperature, as it involves the movement energy of the particles.
What happens when a substance is heated?
-When a substance is heated, energy is transferred to the kinetic energy store of its particles, increasing their internal energy and thereby raising the temperature.
What is specific heat capacity?
-Specific heat capacity is the amount of energy needed to raise the temperature of one kilogram of a substance by one degree Celsius.
How does the specific heat capacity of water compare to mercury?
-Water has a specific heat capacity of 4200 joules per kilogram per degree Celsius, whereas mercury requires only 139 joules per kilogram per degree Celsius.
What is the formula for calculating the change in internal energy?
-The change in internal energy is equal to the mass times the specific heat capacity of the substance times the change in temperature.
How can you find the change in temperature from the change in internal energy?
-To find the change in temperature, divide the change in internal energy by the product of mass and specific heat capacity.
What is the specific heat capacity of water?
-The specific heat capacity of water is 4200 joules per kilogram per degree Celsius.
What would be the final temperature of 800 grams of water initially at 20 degrees Celsius after 20 kilojoules of energy has been transferred to it?
-The final temperature would be 25.95 degrees Celsius, or 26.0 degrees if rounded to three significant figures.
Outlines
🔥 Understanding Internal Energy and Temperature
This paragraph introduces the concept of internal energy and its relationship with temperature. It explains that internal energy is the total energy stored by particles in a substance, which includes potential and kinetic energy. The focus is on kinetic energy, which is directly related to temperature, as heating a substance increases its internal energy and thus its temperature. The paragraph also introduces the term 'specific heat capacity,' which quantifies the energy needed to change the temperature of a substance by one degree Celsius. Examples are given to illustrate the varying specific heat capacities of water and mercury.
🌡️ Specific Heat Capacity and Temperature Change Calculation
This paragraph delves into the specific heat capacity, explaining it as the energy required to raise the temperature of one kilogram of a substance by one degree Celsius. It also describes the equation that relates the change in internal energy to mass, specific heat capacity, and temperature change. A practical example is provided to calculate the final temperature of 800 grams of water after it has absorbed 20 kilojoules of energy. The process involves converting units to kilograms and kilojoules, applying the formula, and interpreting the result, which is a temperature increase of 5.95 degrees Celsius, leading to a final temperature of approximately 26.0 degrees Celsius.
Mindmap
Keywords
💡Internal Energy
💡Potential Energy
💡Kinetic Energy
💡Temperature
💡Specific Heat Capacity
💡Joules
💡Kilogram
💡Celsius
💡Change in Internal Energy
💡Energy Transfer
💡Significant Figures
Highlights
The video explores the relationship between an object's internal energy and its temperature using the concept of specific heat capacity.
Internal energy is the total energy stored by the particles of a substance, often divided into potential and kinetic energy.
Potential energy stores like gravitational and elastic potential are not temperature-related and are ignored in this context.
Kinetic energy is the movement energy of particles and is directly related to temperature changes when a substance is heated.
Temperature is a measure of the average internal energy of a substance.
Different materials require varying amounts of energy to increase their temperature, as illustrated by water and mercury examples.
Specific heat capacity is defined as the energy needed to raise one kilo of a substance's temperature by one degree Celsius.
The specific heat capacity can also represent the energy released when a substance cools by one degree Celsius.
An equation is presented to calculate the change in internal energy based on mass, specific heat capacity, and temperature change.
An example problem is provided to find the final temperature of water after energy transfer, using its specific heat capacity.
The calculation involves dividing energy by mass times specific heat capacity to find the change in temperature.
Units must be correctly converted for accurate calculations, such as grams to kilos and kilojoules to joules.
The final temperature of the water is calculated to be 25.95 degrees Celsius after energy transfer.
The video notes that in real-life scenarios, some energy is typically lost to the surroundings as heat.
For classroom experiments, it is recommended to use a lid and insulate the setup to minimize energy loss.
The video concludes with an invitation for viewers to like, subscribe, and stay tuned for future content.
Transcripts
in today's video we're going to look at
how the internal energy of an object
relates to its temperature
using the concept of specific heat
capacity
now the first thing we need to do is
take a look at a few terms
internal energy is the total energy
that's stored by the particles making up
a substance or system
and we often talk about it as if it's
made up of two parts
the potential energy stores
and the kinetic energy stools
the potential energy stores are things
like gravitational and elastic potential
but they're not really related to
temperature so we can pretty much ignore
them in this video
on the other hand kinetic energy is the
movement energy of the particles
and this is the one that's important
whenever you heat up a substance it
transfers energy to the kinetic energy
store of all the particles
and so increases their internal energy
we measure this as an increase in
temperature
because temperature is just a measure of
the average internal energy of a
substance
so the more internal energy that a
substance has
the higher its temperature will be
however some materials require a lot
more energy to increase their
temperature than others
for example water requires four thousand
two hundred joules of energy
to warm one kilo a bit by one degree
celsius
whereas one kilo of mercury can be
heated by one degree celsius with only
139 joules of energy
we call these numbers the specific heat
capacity
which is the amount of energy needed to
raise the temperature of one kilo of a
substance by one degree celsius
it can also be thought of as the amount
of energy released as that substance
cools
so each time our kilo of water cools by
one degree celsius
it will give out 4200 joules of energy
to the surroundings
we can put this idea into an equation
where the change in internal energy
is equal to the mass
times the specific heat capacity for
that particular substance
times the change in temperature
where the triangle's meaning change
and the zero the line through it being a
theta sign which here means temperature
to see how this works let's try a
question
find the final temperature of 800 grams
of water
at an initial temperature of 20 degrees
celsius after 20 kilojoules of energy
has been transferred to it
the specific heat capacity of water is 4
200 joules per kilo per degree
well in order to find the final
temperature what we're really looking
for is the change in temperature
so to get that term by itself we need to
divide both sides by mse
giving us energy divided by mass times
specific heat capacity
equals change in temperature
next we make sure all of our units are
correct
so change 800 grams to 0.8 kilos
and change 20 kilojoules to 20 000
joules
and then plug these values into the
equation
so overall we get a temperature change
of
5.95 degrees
and if we add that onto our original 20
degrees
the final temperature would be
25.95 degrees
or 26.0 degrees if we round it to three
significant figures which we generally
should
one thing to point out here is that in
real life the temperature probably
wouldn't actually increase this much
because some of the energy would be lost
the surroundings
mostly in the form of heat
so if you're going to do this experiment
in a classroom you'd want to make sure
they used a lid and then you insulated
it well
anyway that's everything for this video
so if you liked it then do give it a
like and subscribe and we'll see you
soon
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